Yukki had been playing around Selesnya Charm all game. He had a Scavenging Ooze with 2 counters, and 2 creatures in the graveyard. Cunningham attacks with a 5/5 Wurm token, and Yukki blocks. He then pumps his Ooze up to 5/5, and Cunningham plays Selesnya charm to exile it. He responds with Golgari Charm, shrinking his Ooze to 4/4 (meaning Selesnya charm doesn't exile it), making the Wurm 4/4, so when he activates his Ooze a second time up to 5/5, it kills the Wurm and sticks around. When the Wurm dies, it also kills Cunninghams Elemental token. He wen't from dominate board position, in full control of the game and about to win, to loosing 2 turns later
Bless his light ;_;